#version 330
out vec4 fragColor;
void main (void)
{
    //Draw a 4 x 4 checker
    ivec2 position = ivec2(gl_FragCoord.xy)/8;
    int bright = (position.x+position.y) % 2;
    vec3 color[2]=vec3[2](vec3(.6,.6,.6),vec3(.4,.4,.4));
    fragColor=vec4(color[bright],1.);
}